

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;


public class DBManager {
	public static Connection conn() {
		//连接数据库MySQL
		try {
			Class.forName("com.mysql.jdbc.Driver");
			return DriverManager.getConnection("jdbc:mysql://localhost:3306/emp?useUnicode=true&characterEncoding=UTF-8", "root", "123456");
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		return null;
	}
	public static int excuteUpdate(String sql) {//增删改
		Connection conn=null;
		Statement st=null;
		try {
			conn=conn();
			st=conn.createStatement();
			return st.executeUpdate(sql);
		}catch (SQLException e) {
			e.printStackTrace();
			closeALL(null, st, conn);
			return 0;
		}
		
	}
	public static QueryDataResult excuteQuery(String sql) {//查询
		Connection conn = null; 
		  Statement st = null; 
		  ResultSet rs = null; 
		  try { 
		   conn = conn(); 
		   st = conn.createStatement(); 
		   rs = st.executeQuery(sql); 
		   return new QueryDataResult(conn, st, rs); 
		  } catch (SQLException e) { 
		   e.printStackTrace(); 
		   closeALL(rs, st, conn); 
		   return null; 
		  }
	}
	public static void closeALL(ResultSet rs,Statement st,Connection conn) {
		try {
			if (conn!=null) {
				conn.close();
			}
	        if (st!=null) {
	        	st.close();
			}
	        if (rs!=null) {
	        	rs.close();
			}
		} catch (SQLException e) {
			e.printStackTrace();
		}
	
	
}
}
